This invention relates to dead bolt locks and more particularly to a device preventing pass key retraction of a dead bolt.
1. Field of the Invention
Motels, apartments and the like are customarily provided with dead bolt locks for security of the occupants against unauthorized entry of the premises.
A dead bolt lock includes a plunger, generally referred to as a "bolt", having flat sides which is movable into and out of a complementary receptacle in an adjacent door jamb. The dead bolt lock is operated by a key from the outer side of the door, and is operated by a handle or knob from the inner or room side of the door. The knob is spaced from the inner side of the door by a shaft and is angularly rotated through a substantial angle in moving between locked and unlocked positions. The dead bolt lock can be operated from the inner side of the door by grasping and turning the knob while the dead bolt lock can be operated from the outer side of the door only by turning a key.
When a dead bolt lock is opened by a key, the knob also pivots through a predetermined angle. If pivoting movement of the knob from its locked position to its unlocked position is prevented, the dead bolt lock cannot be opened from the outer side of the door.
The owner and maintenance personnel of for-rent establishments are customarily provided with a pass key permitting them to enter the respective room or suite.
Occasionally the pass key or a duplicate thereof is obtained by unauthorized persons who may then gain entry to the premises while occupied by a customer.
This invention provides a locking arm member, which may be installed and removed by the room occupant, which substantially envelops the dead bolt operating knob on the inside of an entry door to prevent angular rotation of the knob and withdrawing the dead bolt by the use of a pass key.
2. Description of the Prior Art
U.S. Pat. No. 5,193,373, issued Mar. 16, 1993 to Hunt for SECURITY DEVICE FOR DEAD BOLT LOCK, discloses a body member having a space for receiving a dead bolt lock handle and a slidable retainer on the body for locking the handle to the body member with a pin. The pin end of the body member is attached to one end of a flexible connecter having its other end fixed to an attachment plate mounted on the door face above the position of the dead bolt lock which prevents the body member and handle from rotating in response to the use of a dead bolt key on the outside of the door.
U.S. Pat. No. 3,748,882 issued Jul. 31, 1973 to Dusault, Jr. et al for SECURITY LOCK and U.S. Pat. No. 5,000,498 issued Mar. 19, 1991 to Upchurch for INTERIOR DEAD BOLT KNOB FASTENING APPARATUS are believed good examples of the further state-of-the-art.
Each of the above named patents require some portion of the dead bolt knob securing device to be permanently attached to some portion of the door face or the dead bolt lock mechanism, whereas applicant's device simply envelops the major portion of the dead bolt knob on the inside of a door and does not require attachment to the door or the dead bolt lock mechanism and may be easily installed in locking position and removed therefrom and be carried by the owner thereof from room to room.